To safeguard employees from falling into holes where poles are placed, what must be done?

The correct answer focuses on the importance of physical safety measures to protect employees from potential hazards, specifically falling into holes where poles are placed. When dealing with such work environments, having physical guards around the holes is crucial. These guards can take the form of barriers, covers, or any other structures that prevent accidental falls, which significantly contributes to maintaining a safe workspace.

Physical guarding is a proactive approach in workplace safety protocols. It creates a physical barrier that mitigates the risk of accidents, thereby ensuring that employees are not exposed to dangerous situations. This preventative measure aligns with safety regulations and standards designed to protect workers from injuries.

While training and supervision are important components of overall safety, physically guarding the holes directly addresses the immediate hazard, making it the most effective and essential requirement in this context.